The applicant intends to apply recently developed techniques (both morphological and biochemical) to study the regulatory influences of cell size, hormonal stimulation, age, degree of obesity and nutrition of the animals on several important metabolic activities of fat cells, in various mammalian species including the human. Of particular interest are the regulatory mechanisms involved in hexose transport, rate and pattern of glucose metabolism, and lipolysis. The studies are directed to the elucidation of the metabolic capacities of fat cells of different size during the development of obesity. Elucidation of abnormal rates of metabolism or alterations in the regulatory mechanisms in fat cells from obese animals may allow a better understanding of the pathophysiology of obesity and lead to new forms of therapeutic intervention in obesity, thus retarding or preventing the medical complications associated with obesity. BIBLIOGRAPHIC REFERENCES: DiGirolamo, M., and J. Esposito. Adipose tissue blood flow and cellularity in the growing rabbit. Am. J. Physiol. 229:107-112, 1975. Bradley, E. L., III, and M. DiGirolamo. Remnant function after subtotal thyroidectomy for Graves' disease. South. Med. J. 68:1245-1248, 1975.